Recent advances in dense sensor array technology have opened the way for new insights into human brain electrical fields. Although source localization methods may reveal the sources of electrical fields in neural tissue, these methods remain highly inferential. The present project would develop advanced software for imaging the electrical fields of the human brain at the head surface, drawing on recent developments in workstation graphics and optical data storage. With dense sensor array measurement, the head surface field may be specified with precision, avoiding the common errors of interpolation seen with conventional EEG mapping software. By validating the electrical display with statistical measures, an empirical basis for the imaging process may be established. The proposed Phase II experiments would characterize the relation of the head surface potential field with reference-independent measures, and contrast it with the current density field shown by Laplacian measures. The Surface Imaging Program resulting from this project would allow accurate imaging of brain electrical fields at the head surface, providing a solid basis in measurement for future advances in anatomically-specified electrical source localization. PROPOSED COMMERCIAL APPLICATION: Conventional EEG undersamples the scalp electrical field, such that conventional EEG brain mapping may produce misleading results. Optimized for 128- and 256-channel arrays, the Surface Imaging Program could prove a useful adjunct to interpreting waveform digital EEG in routine neurological practice.